Now, Haruyasumi was started. I have already finished all of classes, Japanese exam and reports. (Yeah! I pass the exam) Everyday, I have only experiment to do. Now, I have finished my old experiment about the effect of copper wire in the recovery of plastics and valuable metals from small home appliances by using Jig separation and now, i start to write paper about this and start new experiment about the recovery of valuable metals from fine particle of computer's print circuit boards by using Knelson Concentrator (Centrifugal Gravity Separator) and Hydrocyclone.